State Key Laboratory on Advanced Displays and Optoelectronics Technologies, Department of Electronic & Computer Engineering, Hong Kong University of Science and Technology , Hong Kong.
Department of Physics and Materials Science and Centre for Functional Photonics (CFP), City University of Hong Kong , Hong Kong.
ACS Nano. 2015 Nov 24;9(11):11049-55. doi: 10.1021/acsnano.5b04483. Epub 2015 Oct 16.
One-dimensional semiconductor nanorods are a very promising class of materials for applications in modern optoelectronic devices, such as light-emitting diodes, solar cells, displays, and lasers. Their ability to emit linearly polarized light is considered to simplify device structures and improve the overall efficiencies. To ensure macroscopic polarization in such devices, the biggest challenge is the long-range alignment of nanorods by controllable means. We propose a technique that combines photoinduced alignment with nanorod's self-assembly. With this approach, we are able to actively control the alignment directions of highly emissive semiconductor nanorods in both microscopic and macroscopic scale with the order parameter as high as 0.87. As a result, polarized emission has been achieved with the degree of polarization of 0.62. Furthermore, patterned alignment of nanorods with spatially varying local orientations has been realized to demonstrate the great flexibility of this approach. Besides opportunities for applications, our method of alignment offers insights into host-guest interactions governing self-assembly of colloidal nanocrystals within the host molecular matrix.
一维半导体纳米棒是一类很有前途的材料，可应用于现代光电设备，如发光二极管、太阳能电池、显示器和激光器。它们能够发射线性偏振光，这被认为可以简化器件结构并提高整体效率。为了确保此类器件具有宏观偏振，最大的挑战是通过可控手段实现纳米棒的长程排列。我们提出了一种将光诱导取向与纳米棒自组装相结合的技术。通过这种方法，我们能够以高达 0.87 的序参数，在微观和宏观尺度上主动控制高度发光的半导体纳米棒的取向方向。结果，实现了偏振发射，其偏振度为 0.62。此外，还实现了纳米棒的图案化排列，具有空间变化的局部取向，展示了这种方法的极大灵活性。除了应用机会之外，我们的取向方法还为了解主体分子基质中胶体纳米晶体的自组装所控制的主客体相互作用提供了深入的见解。
